How do I split a PDF into separate files programmatically?

You can split a PDF programmatically in several ways, depending on your language and whether you want to split by pages, ranges, or bookmarks. Here are common approaches.

1) Python

Using pypdf

Install:

pip install pypdf

Split into single-page PDFs:

from pypdf import PdfReader, PdfWriter

input_pdf = "input.pdf"
reader = PdfReader(input_pdf)

for i, page in enumerate(reader.pages):
    writer = PdfWriter()
    writer.add_page(page)
    output_name = f"page_{i+1}.pdf"
    with open(output_name, "wb") as f:
        writer.write(f)

Split into page ranges:

from pypdf import PdfReader, PdfWriter

reader = PdfReader("input.pdf")

ranges = [(0, 2), (3, 5)]  # pages 1-3 and 4-6
for idx, (start, end) in enumerate(ranges, 1):
    writer = PdfWriter()
    for i in range(start, end + 1):
        writer.add_page(reader.pages[i])
    with open(f"part_{idx}.pdf", "wb") as f:
        writer.write(f)

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2) JavaScript / Node.js

Using pdf-lib

Install:

npm install pdf-lib

Example:

const fs = require("fs");
const { PDFDocument } = require("pdf-lib");

async function splitPdf(inputPath) {
  const pdfBytes = fs.readFileSync(inputPath);
  const pdfDoc = await PDFDocument.load(pdfBytes);

  for (let i = 0; i < pdfDoc.getPageCount(); i++) {
    const newPdf = await PDFDocument.create();
    const [copiedPage] = await newPdf.copyPages(pdfDoc, [i]);
    newPdf.addPage(copiedPage);

    const outBytes = await newPdf.save();
    fs.writeFileSync(`page_${i + 1}.pdf`, outBytes);
  }
}

splitPdf("input.pdf");

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3) Java

Using Apache PDFBox

Add dependency:

<dependency>
  <groupId>org.apache.pdfbox</groupId>
  <artifactId>pdfbox</artifactId>
  <version>2.0.30</version>
</dependency>

Split into single pages:

import org.apache.pdfbox.pdmodel.PDDocument;
import java.io.File;
import java.io.IOException;

public class SplitPdf {
    public static void main(String[] args) throws IOException {
        try (PDDocument document = PDDocument.load(new File("input.pdf"))) {
            int pageCount = document.getNumberOfPages();
            for (int i = 0; i < pageCount; i++) {
                try (PDDocument newDoc = new PDDocument()) {
                    newDoc.importPage(document.getPage(i));
                    newDoc.save("page_" + (i + 1) + ".pdf");
                }
            }
        }
    }
}

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4) Command-line tools from code

If you’re okay calling a system tool:

pdftk

pdftk input.pdf burst output page_%02d.pdf

qpdf

qpdf input.pdf --split-pages -- page-%d.pdf

Or from a script using subprocess / exec.

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Choosing an approach

• Python: easiest for quick automation
• Node.js: good for web/backend apps
• Java: robust for enterprise apps
• CLI tools: simplest if you just need a utility

If you want, I can also give you:

1. a version that splits by specific page ranges,
2. a version that splits by bookmarks/sections, or
3. a ready-to-run script in your preferred language.